Various types of machines have been developed for precision package filling; incorporating a number of different technologies. U.S. Pat. No. 4,095,723 issued to Lerner incorporates a feed pan with two discharge openings leading to a batching hopper. A weighing unit monitors the weight of articles in the bucket and signals a door to close one of the openings as the weight of articles in the bucket approaches a predetermined limit. The weighing unit subsequently signals the feed pan drive to slow and finally stop its feeding action as the limit is reached.
U.S. Pat. No. 4,129,189 issued to Maglecic, controls the weights of charges of product by feeding the product at a high flow rate and then at a relatively low "dribble" flow rate into one or more receiving pans. U.S. Pat. No. 4,664,200, issued to Mikami et al utilizes a plurality of feed troughs adapted to be separately vibrated and radially arranged around the outer periphery of a dispersion table to feed articles to associated weighing units. U.S. Pat. No. 5,473,703 issued to Smith uses a photoelectric counting means to vary the speed of the vibratory feed mechanism as does U.S. Pat. No. 5,671,262 issued to Boyer et al.
While other variations exist, the above described designs for package filling machines are typical of those encountered in the prior art. It is an objective of the present invention to provide for precision filling of packages with parts or material of various sizes and configurations. It is a further objective to provide such precision filling at commercially realistic speeds. It is a still further objective of the invention to provide the above described capabilities in an inexpensive and durable machine which is capable of extended duty cycles and that may be easily repaired and maintained. It is yet a further objective to permit the weighing and counting of parts having specialized shapes and sizes.
While some of the objectives of the present invention are disclosed in the prior art, none of the inventions found include all of the requirements identified.